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The magnetocaloric and electrical properties in annealed Si-doped Ni48Mn39In13-xSix Heusler alloy ribbons with x=0–3 have been investigated. These ribbons crystallize in a partially ordered B2 phase structure. It was observed that both the martensitic structural transition TM and the Curie temperature TC of austenitic phase decrease with increasing Si contents. The small amount of Si in the In position modifies the peak value of positive magnetic entropy change \Delta SM for a magnetic field change H=50\ kOe, which vary from 20.2 J\cdot kg^-1\cdotK^-1 for x=0 to 23.1 J\cdot kg^-1\cdotK^-1 for x=1, and then decrease to 10.1 J\cdot kg^-1\cdotK^-1 for x=3. Meanwhile, the magnetoresistance associated with the martensitic transformation was found to be -45% for x=2 at T=192\ K for a magnetic field change of 50 kOe. [ABSTRACT FROM AUTHOR]

We have studied the effects of partial substitution of In by Si on the magnetic and exchange bias properties of bulk Ni50Mn35In15 Heusler alloys through magnetization measurements. Zero-field and field-cooled magnetization measurements were performed in fields up to 5 T. It was observed that an increase in the Si concentration strongly affects the ground state of the martensitic phase and the magnetic properties of compounds. It was found that exchange bias increases with increasing conduction electron concentration, and the maximum bias field was found to be ≈0.017 T at S K for a cooling field of H = 5 T. [ABSTRACT FROM AUTHOR]